It’s hard to judge quite a detailed crossover when I know nothing about it, but this was also very accessible, with a nicely characterised TARDIS team (little details like Rory’s choice to stand back, so he’d be available to use his nursing skills to pick up the pieces if / when things when wrong, Eleven’s quirkiness, and Amy’s forthrightness are all well-used here), and if the crossover characters are as well done, then definitely one for fans to catch.